Distributive Quantization Codes for Finite Rate Feedback-Based Small Cells

Resource-constrained small cells (SCs) require a distributive and dynamic codebook that adapts to the rapid incoming and outgoing clients, which is in contrast with large centralized codebooks for many traditional finite rate feedback (FRF) systems. This paper discusses the distributive and dynamic codebook approach for SCs. The mapping strategy for the quantization codes to the possible combination of outcomes of the code generator is meticulously detailed. To contain the code quantization error (CQE), which could occur due to the quantization of two or more channel realizations with a single quantization code, we propose a simple and pragmatic null algorithm for the codebook. The efficiency of the algorithm in reducing CQE in a codebook is presented with an analytical expression. We observe that the efficiency of the algorithm in reducing CQE increases with increasing receiving antennas, which is suitable for the densely deployed SC environment. Our simulated study shows that for given quantization codes <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$B^{\prime}$</tex>, number of transmitter antennas <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N$</tex> and number of receiver antennas <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$M^{\prime}$</tex>, the efficiency of the algorithm in reducing CQE in a codebook is found to be as high as 97.8 %.